3Com 4500G Family Configuration Manual page 53

Table 1-1 Class-two configurations
Item
Port isolation
QinQ
VLAN
MAC address learning
Class-two configurations made on an aggregate interface are automatically synchronized to all its
member ports. These configurations are retained on the member ports even after the aggregate
interface is removed.
Any class-two configuration change may affect the aggregation state of link aggregation member
ports and thus ongoing traffic. To make sure that you are aware of the risk, the system displays a
warning message every time you attempt to change a class-two configuration setting on a member
port.
Class-one configurations, which are configurations that do not affect the aggregation state of the
member port even if they are different from those on the aggregate interface. GVRP and MSTP
settings are examples of class-one configurations.
Reference port
When setting the aggregation state of the ports in an aggregation group, the system automatically picks
a member port as the reference. This port is called the reference port of the aggregation group. The port
attribute and class-two configurations of every other member port are compared with those of the
reference port.
IEEE 802.3ad LACP protocol
The IEEE 802.3ad Link Aggregation Control Protocol (LACP) enables dynamic aggregation of physical
links. It uses link aggregation control protocol data units (LACPDUs) for exchanging aggregation
information between LACP-enabled devices.
1) LACP functions
Based on the fields carried in LACPDUs, the functions delivered by the IEEE 802.3ad LACP fall into
basic LACP functions and extended LACP functions, as described in
Whether the port has joined an isolation group
QinQ enable state (enable/disable), TPID for VLAN tags, outer VLAN
tags to be added, inner-to-outer VLAN priority mappings, inner-to-outer
VLAN tag mappings, inner VLAN ID substitution mappings
Permitted VLAN IDs, default VLAN, link type (trunk, hybrid, or access), IP
subnet-based VLAN configuration, protocol-based VLAN configuration,
VLAN tag mode
MAC address learning capability, MAC address learning limit, forwarding
of frames with unknown destination MAC addresses after the MAC
address learning limit is reached
1-3
Considerations
Table 1-2.